Rough idle, stalling, shifting hard

the shifting problem could just be a slipping transmission. how many miles are on the car? also even if fluid is full it could be burned. Check for color and smell. Have you recently flushed transmission fluid?

I have a 2001 cavalier 2.4L auto and have seen some situations which has caused this condition. I had a K&N filter which had clogged the mass air flow sensor causing faulty readings cause this. I've accidently disconnected the mass air flow sensor and caused this but also had HARD shifts followed with slipping gears. The TPS sensor which you've already changed. A loose battery cable has also done this to me. I'm lucky enough to have a mechanics code reader at hand to show code history that was stored and fix the problem. But i have had to take it to a shop before and pay for the reading and have them print off the list and start with the cheapest fix.